Coal in its virgin state is sometimes processed to improve it's usefulness and thermal energy content. The processing can include drying the coal and subjecting the coal to a pyrolysis process to drive off low boiling point organic compounds and heavier organic compounds. Coal is sometimes also subjected to coal gasification and coking operations which produce gas, liquid, and solid products. The liquid product or CDL is a coal tar or coal liquid and is not suitable as a feedstock for typical petroleum refinery operations due to the high oxygen and nitrogen content and its acid number. It may be used as a fuel but its value is typically less than bunker C oil. Its value is also reduced because it is not generally compatible with and can not be blended with most petroleum based fuels.
It would be advantageous if the CDL could be processed into higher value products.